Pesticides as Endocrine Disruptors in South Africa: Laboratory and Field Studies

Expanded Title:

Endocrine disruption (ED) in organisms may be caused by a wide range of natural and synthetic substances (from both diffuse and point sources). The overall objective of this project was to examine potential endocrine disrupting activity posed by the pesticides used in South Africa, as well as the interactive effects of pesticide mixtures, on selected aquatic species.
Controlled laboratory exposure studies were conducted, using two species, the amphibian, Xenopus laevis and the fresh water fish, Oreochromis mossambicus. Insecticides, herbicides and fungicides, were tested in vivo and in vitro, laboratory and field respectively. The results clearly proved the impact of the chemicals. Several formulations were found to be embryotoxic to the Xenopus laevis and significant growth disruption was revealed. Toxic effects were also revealed on the fish. It is strongly recommended that pesticides and herbicides currently used in the intensive agriculture practices, as well as terrestrial and aquatic alien plant require more careful assessment and application, in order to reduce impacts on aquatic organisms in particular.
A link between EDCs in potentially contaminated freshwater systems, and altered endocrine activity/function in exposed wildlife and humans has been demonstrated. But more research is needed, specifically into the effect of insecticide /herbicide mixtures.